Math Problem Statement

f(x) = 2sin(πx + 11π/10) is a transformation of g(x) = sin(x). Describe the transformations, find the period, amplitude, and phase shift, and graph one cycle of the function.

Solution

Problem Analysis and Solutions:

The given function f(x)=2sin(πx+11π10)f(x) = 2 \sin\left(\pi x + \frac{11\pi}{10}\right) is a transformation of g(x)=sin(x)g(x) = \sin(x).

Part (a): Describe the transformations

  1. Vertical Stretch: The coefficient 22 before the sine function indicates a vertical stretch by a factor of 2. The amplitude of the sine wave is doubled.
  2. Horizontal Compression: The coefficient π\pi inside the argument compresses the period of the sine wave. The period is affected and calculated later.
  3. Phase Shift: The term +11π10+\frac{11\pi}{10} inside the argument indicates a phase shift to the left by 11π10π=1110\frac{11\pi}{10\pi} = \frac{11}{10} units.

Part (b): Find the period, amplitude, and phase shift

  1. Amplitude: The amplitude is the absolute value of the vertical stretch factor, which is 2=2|2| = 2.
  2. Period: The period is calculated using the formula: Period=2πcoefficient of x=2ππ=2\text{Period} = \frac{2\pi}{\text{coefficient of } x} = \frac{2\pi}{\pi} = 2
  3. Phase Shift: The phase shift is calculated as constant added to xcoefficient of x-\frac{\text{constant added to } x}{\text{coefficient of } x}: Phase Shift=11π10π=1110\text{Phase Shift} = -\frac{\frac{11\pi}{10}}{\pi} = -\frac{11}{10} Thus, the phase shift is 1110\frac{11}{10} units to the left.

Part (c): Graphing one cycle of f(x)f(x)

To graph:

  1. The period of the function is 2, so one cycle occurs from x=1110x = -\frac{11}{10} (starting phase shift) to x=1110+2=910x = -\frac{11}{10} + 2 = \frac{9}{10}.
  2. Divide the cycle into four equal intervals (quarter-periods) for key points:
    • Starting point: x=1110x = -\frac{11}{10}, f(x)=0f(x) = 0
    • First peak: x=1110+12=610x = -\frac{11}{10} + \frac{1}{2} = -\frac{6}{10}, f(x)=2f(x) = 2
    • Midpoint (zero): x=1110+1=110x = -\frac{11}{10} + 1 = -\frac{1}{10}, f(x)=0f(x) = 0
    • First trough: x=1110+32=410x = -\frac{11}{10} + \frac{3}{2} = \frac{4}{10}, f(x)=2f(x) = -2
    • End point: x=1110+2=910x = -\frac{11}{10} + 2 = \frac{9}{10}, f(x)=0f(x) = 0

I can plot this for you to visualize the transformation. Let me know if you'd like me to generate the graph for clarity. Would you like details about these steps or any related questions answered?


Questions to Explore Further:

  1. How do transformations like vertical stretches affect the sine function's range?
  2. What is the relationship between period and frequency in trigonometric functions?
  3. How does a phase shift affect the symmetry of the graph?
  4. What happens to the graph if the amplitude is a fraction (e.g., 12\frac{1}{2})?
  5. How would a negative amplitude (e.g., 2-2) affect the graph?

Tip:

When graphing trigonometric functions with transformations, always mark the amplitude, period, and phase shift clearly for accuracy

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Math Problem Analysis

Mathematical Concepts

Trigonometric Transformations
Amplitude
Period
Phase Shift
Graphing Trigonometric Functions

Formulas

Amplitude = |a| where a is the coefficient of sin or cos.
Period = 2π / (coefficient of x in the argument of sin or cos).
Phase Shift = - (horizontal shift constant) / (coefficient of x in the argument).

Theorems

Basic properties of sine function transformations

Suitable Grade Level

Grades 10-12